You should be able to just change the png files within the systemui.apk (located /system/app/)
There are numerous way to do this... here's what I do
- Reboot into recovery
- MAKE A NAND BACKUP
- Go to mounts and mount /system
- Copy systemui.apk file to a local PC (I use Droid Explorer, shows name as "Status bar")
- Use 7zip to open
- extract the "res" folder
- replace the "stat_sys_data_connected_3g, stat_sys_data_fully_connected_3g, stat_sys_data_fully_in_3g, etc..." png files with whatever you want (I'd ensure the size is roughly the same (38x38). png files are in the drawable-hdpi folder within the res folder
- Replace the res folder within the apk using 7-zip
- DELETE the systemui.apk on the phone with the one you just created
- reboot
Enjoy...
You can also play with the png files within the framework.apk file located in /system/framework. Lots of options
